finding 5.4 : emergence-new-vectorborne-pathogens

Vector-borne pathogens are expected to emerge or reemerge due to the interactions of climate factors with many other drivers, such as changing land-use patterns [Likely, High Confidence]. However, the impacts to human disease will be limited by the adaptive capacity of human populations, such as vector control practices or personal protective measures [Likely, High Confidence].

Process for developing key messages: The chapter was developed through technical discussions of relevant evidence and expert deliberation by the report authors at several workshops, teleconferences, and email exchanges. The authors considered inputs and comments submitted by the public, the National Academies of Sciences, and Federal agencies. For additional information on the overall report process, see Appendices 2 and 3.

The approach and organization of this chapter was decided after conducting a comprehensive literature review. Two case studies, Lyme disease and West Nile virus, were chosen as representative examples of vector-borne diseases in the United States for this chapter because of their high incidence rates and the body of literature available on the association between climatic and meteorological variables and occurrence of these diseases.

Regarding human outcomes related to vector-borne diseases, there is a much greater volume of published literature available on meteorological and climatic influences on vectors. As a result, our certainty in how climate change is likely to influence the vectors far exceeds our certainty in how changing climatic conditions are likely to affect when, where, and how many cases of vector-borne diseases are likely to occur.

Although the topic of zoonotic diseases was included in the original prospectus, it was later removed due to space constraints. Additionally, since both West Nile virus infection and Lyme disease are zoonotic diseases, these case studies address concepts that are common to both vector-borne and zoonotic diseases.

New information and remaining uncertainties: It remains uncertain how climate interacts as a driver with travel-related exposures and evolutionary adaptation of invasive vectors and pathogens to affect human disease. Improved longitudinal datasets and empirical models that include vector–host interaction, host immunity, and pathogen evolution as well as socioeconomic drivers of transmission are needed to address these knowledge gaps in research on climate sensitive diseases.

Assessment of confidence based on evidence: Based on the evidence, there is high confidence that a multitude of interacting factors, one of which being climate change, will likely influence the emergence or reemergence of vector-borne pathogens to the United States. Additionally, there is high confidence that the influence of climate change on human disease is likely to be limited by the adaptive capacity of a population.